The proposed work is a collaboration between research teams on three continents: Africa (the University of Zambia (UNZA) and Macha Mission Hospital ([MMH], Zambia), North America (Yale University, Tufts University, U.S.), and Europe (Leeds Metropolitan University, UK, and University of Jyv[unreadable]skyl[unreadable], Finland). It builds on the existing Yale-UNZA R21 TW006764, which was funded in 2003 and constituted the foundation for forming a team, developing collaborative relationships, transferring expertise, developing assessment instruments, conducting field research, and collecting preliminary data. Building on this foundation, in this application, we propose to (1) identify, using the assessment instruments developed/validated in our R21, two groups of probands: students with Specific Reading Disability (+SRD, n=400) and students without SRD (- SRD, n=400). Only children with at least an average level of intellectual functioning and with at least one sibling in the age range of 6-21 years will be considered as probands in this grouping. Given our pilot data, we anticipate that screening 3,000 children will provide us with an opportunity to ascertain these two samples of probands and recruit at least 2 family members of these probands. Having constructed these two samples of +/-SRD probands and their families, we will be able to investigated manifestation, epidemiology, and etiology of SRD in Zambia. Specifically, we will (1) characterize SRD in the Nyanja, Tongo, and English languages in Zambia using cognitive models of relative componential processes whose deficits form SRD's foundation;(2) describe the home, school, and community social environment and experience of children with SRD in Zambia;and (3) investigate etiological bases of SRD by considering both environmental (e.g., poverty, orphanhood, environmental toxicity) and genetic factors. All research activities in this application will contribute to strengthening collaborative relationships between the team members and providing training and capacity building for relevant skills at the UNZA and MHH institutional, faculty, and graduate student levels.